Projected line is not visible at face edge

Kevin

When using 'Body.ProjectCurve(.....)' to project a line on to a face, the projected line is not visible if it coincides with a face edge. The image below shows the result of projecting two lines on to the curved top face of a block in the direction of the face normal. Only one curved line is visible, but two lines appear in the modelling browser. If I make the block invisible, the second line still does not show.



If I change the projection angle to 45 degrees instead of 90 degrees, both curved lines are visible as shown below.



Can anyone suggest a fix to make the projected line visible when it coincides with the face edge?

Thanks,

Kevin